224 VETEEINARY PHYSIOLOGY 



injures the capillary wall. Thus the injection of hot water 

 or of proteoses at once leads to an increased flow of lymph. 



While the permeability of the vessel wall is the most import- 

 ant factor controlling lymph formation, any increase of the 

 intra-vascular pressure of a region increases the flow of lymph, 

 and for this reason any obstruction to the free flow of blood 

 from a part leads to increased lymph production from that 

 area. 



That lymph is also formed from the tissues is indicated by 

 the fact that the injection of substances of high osmotic 

 equivalent into the blood such as sugar or sodium sulphate 

 leads, by a process of osmosis, to a flow of fluid into the 

 blood, so that it becomes diluted, and also to an increased 

 formation of and flow of lymph, and this increase of water in 

 both can be explained only by its withdrawal from the 

 tissues. 





